The last decade has seen dramatic advances in the field of endoscopic instrumentation, and the application of endoscopic techniques to a growing number of surgical procedures. The benefits--reduced pain and discomfort, shortened recovery time and better cosmetic results--insure that endoscopic surgery will continue to be a rapidly developing and widely applied technique.
Endoscopic surgery is performed with elongated instruments inserted through small holes in the skin, and is viewed through a video monitor. Therefore, such operations require more mental and physical dexterity than corresponding traditional surgical techniques. Because of these additional difficulties it is important to provide surgical tools that are as trouble free and easy to use as possible.
In endoscopic suturing, the knot must be secure and should be as small as possible to prevent tissue reaction. Stress to the suture weakens its strength and should be minimized. Any crimping or crushing of the suture, or any "sawing" between strands during the knot tying process is to be avoided. If the suture must pass through tissue the knot tying can be done extracorporeally or intracorporeally. If ligation is required a slipknot can be tied in the suture beforehand. Ligation is clearly the simpler suturing technique and therefore the method of choice when there is an option. Endoscopic ligatures are used to ligate vessels and tissue pedicles and to close the openings of cystic structures to prevent spillage contamination.
The state of the present technology in endoscopic ligating instruments is represented by the ENDOLOOP.TM. manufactured by Ethicon, a Johnson & Johnson Company, and the Surgitie.TM. Ligating Loop manufactured by Auto Suture Company, a division of United States Surgical Corporation. These endoscopic ligating instruments have an elongated bored staff with a suture threaded therethrough, the suture forming a loop at the intracorporeal end of the staff. The trocar is provided with a seal mechanism which can form an air-tight seal with the instrument upon insertion of the instrument into the cannula of the trocar. The segment of the staff extending past the seal remains outside the body during surgery and is used as a handle to position the loop. At the extracorporeal end of the staff the suture is connected to a short pull rod that is bonded to the staff. The bond is easily broken by a manual force. The loop is closed by pulling the rod away from the staff.
The instrument is used by placing the loop next to a tissue pedicle or vessel, gripping the tissue with a grasping tool, pulling the grasped tissue through the loop and tightening the loop by separating the pull rod from the staff and pulling it away from the staff.
A drawback of these instruments is that the flexibility of the suture necessary for ligature purposes makes the position and configuration of the loop susceptible to surface tension forces exerted by body fluids. In particular, the surface tension can cause a suture to collapse on itself, closing the loop. It is then difficult to reopen the loop with endoscopic tools, and such manipulations present the risk of inadvertently stressing the suture. Also a wetted suture will tend to adhere to wet surfaces, making it difficult to position the loop in close proximity to tissue. This problem is compounded by the fact that when the suture is wetted, the moisture softens the material. Gut suture is somewhat more impervious than braided Nylon or silk to this softening problem.